Printing cylinder

ABSTRACT

A printing cylinder useful in rotary printing presses is provided with construction features whereby a flexible printing plate having leading and trailing edges flanged at essentially right angles to the plate principal printing surface may be conveniently and reliably secured to the printing cylinder for printing at high rotational speeds.

United States Patent Etchell et al.

[ Sept. 11, 1973 PRINTING CYLINDER Inventors: Gordon Etchell, Downers Grove;

Bohdan Washchynsky, Westchester, both of 111. 4

North American Rockwell Corporation, Pittsburgh, Pa.

Filed: June 12, 1972 Appl. No.: 261,864

Assignee:

US. Cl. l0l/4l5.l, l01/378 Int. Cl B411 27/06 Field of Search l0l/4l5.1, 378

References Cited UNITED STATES PATENTS .10/1956 Park et a1. l0l/4l5.l l/l962 Luehrs 101/415.1

3,095,811 7/1963 Peabody et al. l0l/4l5.l 3,188,952 6/1965 Miller l0l/4l5.1 3,425,348 2/1969 Hennach et a1. l0l/4l5.l 3,608,487 9/1971 Luehrs l0l/4l5.l 3,626,848 12/1971 Tafel et al l0l/4l5.l

Primary Examiner-Robert E. Pulfrey Assistant ExaminerPaul T. Sewell Attorney-.lohn R. Bronaugh et a1.

A printing cylinder useful in rotary printing presses is provided with construction features whereby a flexible printing plate having leading and trailing edges flanged at essentially right angles to the plate principal printing surface may be conveniently and reliably secured to the printing cylinder for printing at high rotational-speeds.

ABSTRACT 2 Claims, 9 Drawing Figures Patented Sept. 11, 1973 3,757,691

2 Sheets-Sheet l Patented Sept. 11, 1973 PRINTING CYLINDER SUMMARY A printing cylinder of the type utilized in rotary printing presses is provided with a novel lockup construction whereby the flanged leading and trailing edges of a flexible printing plate, formed essentially at right angles to the plate printing surface and having retention slots, cooperate with elements of a U-shaped restraining/tensioning spring member extending throughout the longitudinal extent of the cylinder lockup trough. The printing cylinder lockup is also provided with an elongated actuator means essentially coextensive with the restraining/tensioning spring member for operatively, alternately securing or releasing the plate leading and trailing flanged edges to and from the printing cylinder body. In one embodiment of the invention the U-shaped spring member is actuated by a single actuator cam and shaft combination positioned intermediate upstanding spring leg elements. In an alternate embodiment of the invention each one of a pair of cam and shaft actuators cooperate with one of the restraining/tensioning spring member upstanding leg elements. In both embodiments of the invention the U- shaped spring member is characterized by the inclusion of opposed upstanding leg elements anchored to the printing cylinder body. The upstanding leg elements are each comprised of first finger elements for radially restraining and clamping the" plate leading edge when actuated in one direction and for tensioning the plate by cooperation with the plate trailing edge when actuated in an opposite direction. The first finger elements in each upstanding leg are alternated with second finger elements for radially restraining the plate trailing edge when actuated in such opposite direction.

DRAWINGS FIGS. 1 through 3 are sectional views of a preferred embodiment of a printing cylinder having a flexible printing plate restraining/tensioning spring and single actuator lockup combination'in accordance with this invention in different actuated conditions;

FIG. 4 is a fragmentary perspective view of a flanged edge of the flexible printing plate secured to the printing cylinder of the drawings; I

FIG. 5 is a detailed perspective view of the elongated, U-shaped spring member utilized in the printing cylinder lockup of the drawings;

FIG. 6 is a partial sectional view illustrating actuation of the printing cylinder lockup of the drawings to secure the flexible printing plate flanged leading edge;

FIG. 7 is a partial sectional view illustrating actuation of the printing cylinder lockup of the drawings to secure the plate trailing edge; and 1 FIGS. 8 and 9 are fragmentary sectional views of a printing cylinder embodiment in accordance with this invention having paired actuators for actuating the U- shaped restraining/tensioning spring member to sucure a flexible printing plate to the printing cylinder body.

DETAILED DESCRIPTION The printing cylinder of this invention is of the type generally illustrated in US. Pats. Nos. 3,095,811, 3,335,663 and 3,626,848, assigned to the assignee of this application. As shown in FIGS. 1 through 3 of the accompanying drawings, a rotaryprinting press printing cylinder 10 is provided with an improved tension lockup in accordance with this invention for conveniently and reliably securing flexible printing plate 11 to the cylinder body for use in printing at high rotational speeds. Printing plate 11, sometimes commonly referred to as a wrap-around printing plate, is wellknown in the art and is provided flanges 12 formed at essentially right angles to the principal plate printing surface at the plate leading and trailing edges. Each flange 12 is provided with elongated slots 13 for use in radially restraining the plate leading edge in a proper position on cylinder 10 and with elongated slots 14, offset from the line of and alternated with respect to slots 13, for radially restraining the plate trailing edge in proper position with respect to cylinder 10. Slots 14 are preferably located in flange 12 near the junction of flange 12 with the principal plate surface. Locating holes 15 (see FIG. 4, for an example) are provided in each leading/trailing edge of plate 11 for cooperation with locating studs (31, FIG. 6) located on the cylinder lockup trough edges to obtain proper registration of plate 11 with printing cylinder 10. Circumferential registration of plate 11 with printing cylinder 10 is obtained by the abutting relation of the flange 12 at the plate leading edge with the cooperating lockup trough edge.

The lockup arrangement employed in the printing cylinder 10 of this invention is shown in one embodiment in FIGS. 1 through 3, and in another embodiment in FIGS. 8 and 9. As shown in the FIG. 1 arrangement, lockup is essentially comprised of an elongated restraining/tensioning spring member 16 of generally U- shaped cross sectional configuration secured at its base in a fixed position in the lockup trough or recess of cylinder 10 by support bar 17 which is fastened to cylinder 10 by coacting countersunk screws which extend into the cylinder not shown. An elongated cam 18 and its supporting shaft 19 are located in the FIG. I arrangement intermediate the spring upstanding leg elements 20 and 21. Shaft 19 of the lockup actuator is journaled at opposite ends, and sometimes at intermediate positions, to the body of cylinder It) and one end thereof extends beyond the cylinder body to receive a conventional operating lever or other device is normally mechanically joined to shaft 19 on the portion outside of the cylinder body for use in effecting its rotation and concurrent retention/release of printing plate 11 to cylinder 10 as hereinafter described.

The lockup incorporated in the printing cylinder of this invention includes one or more elongated spring member segments such as 16 having elements for cooperation with slots 13 and 14 and surface portions of flange 12 of each leading or trailing edge of printing plate 11. Such elements correspond in number and location or position (installed) to obtain registration with the slots and flange bends provided in plate 11. As shown in FIG. 5, spring member 16 is of one piece construction with legs 20 and 21 integrally joined to base portion 22. Slots 23 are provided in base portion 22 for optional use in securing'spring 16 in a fixed position in the longitudinal trough of cylinder 10 as by the use of fasteners. See FIGS. 8 and 9.

Each upstanding leg element 20 or 21 of spring member 16 is provided with finger elements 24 and alternate finger elements 25 throughout the longitudinal extent of the lockup. Each finger element 24 has an inturned flange 26 whose inward edge functions to engage the downturned flange 12 of plate 1 1 in the region of the junction of flange 12 with the plate principal surface when actuated for the purpose of tensioning such plate 11. Each finger element 24 is also provided with a nose portion 27 for clamping, and with a tab portion 28 for radially restraining, the flanged edge 12 of plate 11 serving as a leading edge in proper position. The inturned flange 29 on each finger element 25 is provided for engaging (and radially restraining) plate 11 at slots 14 of flange 12 of the printing plate edge serving as a plate trailing edge. Narrow slits 30 are provided in the FIG. illustrated segment of spring member 16 for the purpose of in-part defining and separating the different finger elements from each other. In the printing cylinder arrangement of the drawings each upstanding leg of a segment of spring member 16 is provided with a pair of finger elements 24 with one intermediate finger element 25. An alternate spring member arrangement (not shown) includes a pair of end finger elements 25 with an intermediate finger element 24. Alternatively elements 24 may be alternated with elements 25 throughout the length of the restraining/tensioning spring member incorporated in the printing cylinder lockup assembly, although for symmetry and reversal reasons it is preferred that the end slots in each flange 12 be of the same type so that the same sequence of slots (and positioning stud openings) can be interchangeably used for either leading edge or trailing edge applications as in instances wherein printing cylinder is to be operated in an opposite rotational direction.

lt should be noted that all tabs 28 of finger elements 24 and inward turned flanges 29 of finger elements 25 are configured to present a radially upward sloped surface (from their line of origin in the upstanding finger element) to the lower edges of cooperating slots 13 and 14 in plate 11. By such sloping tab and flange surfaces being engaged with the corresponding slots 13 and 14 in the flanges 12 of plate 11, counter clockwise movement of the leg elements and 21 in FIG. 1 serves to draw each flange 12 radially downwardly and toward the center of cylinder 10 to obtain a proper radial restraint of the plate leading and trailing edges. As shown more particularly in FIGS. 6 and 7, recesses are provided in each edge of the lockup trough of printing cylinder 10 to receive those portions of tabs 28 that pass through slots 13. The interior edges of flanges 26 on finger members 24 also normally sloped upwardly slightly to eliminate metal to metal interference when engaging the under surface of trailing edge flange 12 in the region where flange 12 is formed at essentially right angles to the principal surface of plate 11.

FIG. 6 provides an enlarged illustration of the leading edge of plate 11 properly radially restrained at flange 12 by a tab 28 and by a nose 27 which clamps the leading edge against the support face 32 of the cylinder. 31 is a locating stud provided in face 32 for cooperation with a locating hole 15 to obtain proper lateral registration of the plate with the cylinder. FIG. 7 provides an enlarged illustration of the trailing edge of printing plate 11 properly radially restrained at flange 12 by an upward sloping flange 29 of finger element 25 and tensioned by engagement with the edges of flanges 26 in lockup arrangement. As shown in FIG. 7, upwardly sloping flange 29 of finger 25 draws flange l2 radially toward the center of cylinder 10 producing a slight inward bend in the principal surface of plate 11 near the edge 32 of cylinder 10 when the lockup mechanism is actuated.

FIGS. 1 through 3 also illustrate the various operating conditions of restraining/tensioning spring member 16 as a result of different degrees of rotation of elongated bar cam 18 and connected shaft 19 comprising the lockup single actuator. In FIG. 1, the right hand flatted portion of bar cam 18 has released one of the identical upstanding leg elements of spring member 16 from engagement with a lockup trough edge of cylinder 10 to permit installation of a flanged edge 12 of plate cylinder 11 at a plate leading edge. In the FIG. 1 condition the other upstanding leg element of spring member 16 is in engagement with the opposite lockup trough v edge of cylinder 10.

In the FIG. 2 arrangement, cam 18 and shaft 19 have been rotated counterclockwise to a position where both upstanding leg elements of spring member 16 are forcefully urged toward engagement with the opposing trough edges in the cylinder 10. Such action properly secures the flanged edge 12 of printing plate 11 intended as a leading edge to the cylinder and permits insertion of the flange l2 intended as the plate trailing edge into the cylinder trough for subsequent radial restraint and tensioning.

In the FIG. 3 illustration, cam 18 and shaft 19 have been rotated clockwise a sufficient degree whereby the upstanding leg of spring member 16 engaging the plate trailing edge has been brought into position by inherently present spring forces to properly radially restrain the trailing edge flange l2 and to simultaneously tension the entire plate. The installed printing plate 11 is then ready for use in high speed printing by the rotary printing press printing cylinder.

The alternate printing cylinder embodiment illustrated in FIGS. 8 and 9 differs from the FIG. 1 through FIG. 3 arrangement primarily in that use is made of a pair of lockup actuators for actuating spring member 16 as distinguished from a single actuator. As shown in FIG. 8 for instance, printing cylinder 40 is provided with lockup actuator cams 41 and 42 that each are secured to one of longitudinal shafts 43 and 44. Shaft 43 and its cooperating elongated cam 41 are journaled in support block 45 of printing cylinder 40. The actuator combination comprised of elongated cam 42 and connected shaft 44 is installed in support block 46 located in the lockup trough or recess of printing cylinder 40 in the manner of block 45. Restraining/tensioning spring member 16 in the FIG. 8 and 9 arrangement is preferably identical to the corresponding spring member in printing cylinder 10 except that it is secured to the printing cylinder 40 by means of conventional screw fasteners 47 and cooperating hold-down bar 48.

FIG. 8 illustrates printing cylinder 40 with the paired lockup actuators operated to a condition whereby both the leading edge and trailing edge flange 12 of printing plate 11 may be readily inserted in the lockup trough for subsequent proper engagement with the lockup subassembly. FIG. 9 illustrates cams 41 and 42 each rotated counterclockwise to properly secure both the leading and trailing edges of plate 11 to printing cylinder 40. The FIG. 8 and 9 printing cylinder construction differs from the FIG. 1 through 3 printing cylinder embodiment in that the tensioning forces applied to flexible plate 11 are developed only partly as a result of the inherent spring forces of spring member 16. Additionally, cam member 41 positively urges the cooperating upstanding leg element of spring member 16 into tensioning engagement with the printing plate trailing edge flange l2. inherent spring forces in spring member 16 only are utilized, however, to properly secure the flanged leading edge of printing cylinder 11 to printing cylinder 40.

What is claimed is:

1. A plate clamping arrangement for a reversible printing cylinder comprising, in combination, a flexible printing plate having flanged and slotted leading and trailing edges formed essentially at right angles to the plate principal surface, a longitudinal trough formed in the surface of said cylinder and defined in part by leading and trailing trough edges, a substantially U-shaped spring member mounted in said trough and extending longitudinally of said cylinder, said spring member having spaced apart, upstanding leg elements each having plate engaging finger elements at the free ends thereof, rotatable elongated cam means mounted in said trough intermediate said leg elements and operable to position the respective leg elements selectively in a printing plate leading edge clamping position wherein the said flanged and slotted leading edge of the plate is clamped between the finger elements and the said trough leading edge or in a printing plate trailing edge tensioning position wherein said finger elements engage the flanged and slotted trailing edge of said plate and bias it circumferentially away from said trough trailing edge, first means on each of said leg elements for engaging the slots in the flanged leading edge of said plate to radially restrain the said leading edge of said plate when said leg element is positioned in the said plate leading edge clamping position, and second means on each of said leg elements for engaging the slots in the flanged trailing edge of said plate to radially restrain the said trailing edge of said plate when said leg element is positioned in said plate trailing edge tensioning position.

2. A plate clamping arrangement as set forth in claim 1 wherein two separate, elongated cam means are mounted in said trough for independently positioning the respective leg elements in their plate clamping or plate tensioning positions. 

1. A plate clamping arrangement for a reversible printing cylinder comprising, in combination, a flexible printing plate having flanged and slotted leading and trailing edges formed essentially at right angles to the plate principal surface, a longitudinal trough formed in the surface of said cylinder and defined in part by leading and trailing trough edges, a substantially U-shaped spring member mounted in said trough and extending longitudinally of said cylinder, said spring member having spaced apart, upstanding leg elements each having plate engaging finger elements at the free ends thereof, rotatable elongated cam means mounted in said trough intermediate said leg elements and operable to position the respective leg elements selectively in a printing plate leading edge clamping position wherein the said flangeD and slotted leading edge of the plate is clamped between the finger elements and the said trough leading edge or in a printing plate trailing edge tensioning position wherein said finger elements engage the flanged and slotted trailing edge of said plate and bias it circumferentially away from said trough trailing edge, first means on each of said leg elements for engaging the slots in the flanged leading edge of said plate to radially restrain the said leading edge of said plate when said leg element is positioned in the said plate leading edge clamping position, and second means on each of said leg elements for engaging the slots in the flanged trailing edge of said plate to radially restrain the said trailing edge of said plate when said leg element is positioned in said plate trailing edge tensioning position.
 2. A plate clamping arrangement as set forth in claim 1 wherein two separate, elongated cam means are mounted in said trough for independently positioning the respective leg elements in their plate clamping or plate tensioning positions. 